Spatial Transcriptomic Atlas Of Temporomandibular Joint Osteoarthritis In Adolescent Mice

Temporomandibular joint osteoarthritis (TMJOA) in adolescent patients can lead to mandibular developmental disorders and deformities. This study aims to investigate spatial gene expression changes of condylar cartilage under inflammatory conditions in adolescent mice. An anterior disc displacement-induced osteoarthritis model was established in 4-week-old C57/BL6 mice. TMJs were harvested after 1 week, and 10x Genomics HD spatial transcriptomic sequencing was employed to analyze cellular heterogeneity in condylar cartilage of normal/ TMJOA mice. Cell types across tissues and marker genes of interest were validated via immunofluorescence and quantitative real-time PCR. The condylar cartilage of adolescent TMJOA mice was classified into seven functionally cell subpopulations. Among these, reparative fibrocartilage cells exhibited significant spatial redistribution under TMJOA stimulation. This subpopulation specifically expressed the Tenascin-C (Tnc). Immunofluorescence and qPCR confirmed the overexpression of TNC in the condylar cartilage of TMJOA mice. Tnc-positive reparative fibrocartilage cells serve as the primary functional cells mediating cartilage repair in the adolescent mice with TMJOA.